Measuring & Monitoring Mountain Biodiversity (M3B) training (18-29^th Nov 2013) in the Manas Park Range, Royal Manas National Park, bagged yet another new bird record for Bhutan, increasing Bhutan’s official bird tally to 689. The latest addition to the birdlist is Larus ridibundus (Black-headed Gull). This is the fourth gull species now known in Bhutan—others are Pallas’s Gull, Slender-billed Gull and Brown-headed Gull. Gulls in Bhutan have been rare partial winter visitors and passage migrants.

On 23^rd November 2013, the participants of the M3B-bird training marched to the shoreline of the mighty Drangme Chu (Manas). The schedule for the day was to conduct waterbird watching along the river from Panbang to Mathang Guri, from inflated raft boats of the Royal Manas National Park. The first batch of participants had already boarded the wooden canoe, which is used to ferry people from the park range campus to the other side of the river. A few of us (Ugyen Tenzin, Tobias Schimid, and others) were walking towards the river a bit late when one of us noticed and shouted, “A bird, a white bird”, watching a white bird in flight along the river from the north. Tobias and Sherub pulled out their Nikon cameras and photographed the bird at high shutter speed. The bird was initially identified as a Brown-headed Gull. But in the evening, upon studying the characteristic field marks from the photograph, it was confirmed as a Black-headed Gull. The Black-headed Gull has a dark red bill and red legs with a dark spot at the ear-coverts, sooty dark above, below and frontal of the eye. The Black-headed Gull is best differentiated from the Brown-headed Gull in flight in having more pointed wings, with white on the outer primaries extending along most of the wing length, rather than in a small area near the wing-tip border. It also has a relatively thin bill and (apparently) dark iris. This species is a regular on the Brahmaputra in Assam.